vfio: Ignore -ENODEV when getting MSI cookie

When we try to get an MSI cookie for a VFIO device, that can fail if
CONFIG_IOMMU_DMA is not set. In this case iommu_get_msi_cookie() returns
-ENODEV, and that should not be fatal.

Ignore that case and proceed with the initialisation.

This fixes VFIO with a platform device on the Calxeda Midway (no MSIs).

Fixes: f6810c15 ("iommu/arm-smmu: Clean up early-probing workarounds")
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

drivers/vfio/vfio_iommu_type1.c

@@ -1787,7 +1787,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 
 	if (resv_msi) {
 		ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
-		if (ret)
+		if (ret && ret != -ENODEV)
 			goto out_detach;
 	}